Years:

Muck is one of Bob's machines from the Bob the Builder theme. He/she was first made in DUPLO in 3274 Bob and Muck Repair the Barn and 3276 Muck and Scoop, both in 2001. When Muck was first released, his/her dumping bed was supported by a single 2x4 plate. This meant it fell off easily since it wasn't strongly connected. In all later sets, the dumping bed is supported by two 2x4 plates placed side by side.